Category Archives: Heathrow weather

Weather models are hinting that this coming bank holiday weekend could be very warm indeed, with one WX Charts animation suggesting that a positive anomaly of 12C could be possible on Monday.

A date record looks a formality and, unless there’s a downgrade, new monthly high temperature records at stations across the south-east look a possibility.

While it looks very warm it is too early to start talking about heatwaves. And, considering the pattern since late February, with hot and cold alternating weekly, a brief return to much cooler conditions at the beginning of June can’t be ruled out.

The British record high temperature for May is 32.8C, reached on two occasions:

Camden Square, London May 22nd 1922. The same station recorded this value again on May 29th 1944, along with Regents Park, Horsham and Tunbridge Wells.

The national date record for the 28th, according to TORRO, is 30.6C at Camden Square.

Locally the highest temperature recorded in this area in May is 32.1C on May 27th 2005. The date record I recorded is 26.5C in 2012.

In terms of climatology November maxima, considering the 1981-2010 average, shows a steady fall until the 15th. And another steady fall to the 22nd before things level off. This would reflect the November singularities; St Martin’s Summer, between 15th and 21st, peaking on the 18th, occurs in 66 per cent of years. The Early December storms singularity can arrive this month, on the 24th, the air off the Atlantic raising the mean temperature.

The average rainfall graphic shows that downpour amounts are variable through the month. A tendency for dry weather around the 15th reflects the St Martin’s Summer singularity.

Like this:

I’ve seen this phrase uttered more than once over the past couple of days thanks to high temperatures and humidity. But ask anyone to define a hot day and you’ll get a different answer every time.

Growing up in the 1970s / 80s redtop newspapers would use the phrase once the mercury was nudging 80F (26.7C). But to ‘scorch’ you need sunshine, preferably at least 10 hours of it. Considering statistics from the Heathrow airport climate station in west London there have been 463 scorchers since 1959, the most recent happening on July 5th with 29.5C recorded and 13.9 hours of sunshine. There have now been 9 scorchers this year, already matching the number that were recorded in 2014 and only 3 short of last year.

But even with last month’s heatwave this year has some way to go, however, to match the amount measured in 1976 and 1995: 31 days!

Sunsets

With the sun lower in the sky at this time of year there’s often a great opportunity for a decent sunset

I took this yesterday evening. Windless, still and humid at ground level it was fascinating to look skyward and see the multi-level cloud continue to build into strange shapes, illuminated from below by the setting sun. A wonderful weekend for cloudspotting.

Sunset Southwark Bridge

A stunning example of sunlight illuminating the underside of cloud at sunset was seen mid-month

It was a month with some amazing sunsets. This one, on April 30th, happened just as the sky cleared before dusk

Sunset on 31st looking across Wanstead Flats. July was a classic summer month for weather

Typical April days of sunshine and showers were in short supply. There were some stunning sunsets, including this one on the 30th

Sunset on Wanstead Flats

sunset overlooking Wanstead Flats 2nd August

Satellite images

Ophelia

Both the 2013 storm, left, and the 1987 storm followed a similar track as shown on these satellite pictures

On 25th a perfect curl could be seen on a depression centred off the west coast of Irleland. The rain associated with this low pressure brought the month’s highest daily rainfall total: 23.4mm (the system bringing 27.5mm) – a thoroughly miserable Bank Holiday Monday where it rained ALL day, from 6am until 9.30pm. It was yet another example of how much even frontal rainfall can vary over a small area.

This satellite picture taken on December 27th, 2014, shows the LP clearing through to leave us in clear, deep cold air